Hi and welcome!
Have your pup use it before you get to the airport and no more food till after the flight. Put a little stuffed toy or small pillow that she can lay on. Put her favorite blankie in there and carry some treats with you. Have some nutrical handy and try not to give water till after the flight. I still took some pads with me and laid one on the bathroom floor so Kodak could pee when I went to the bathroom. I then took him to pee as soon as we got off the flight outside. If the flight is a short one, your pup should be ok, just make her comfortable. I've even heard people saying they put their sock in the carrier so the pup can smell them at all times.